Storage and retrieval apparatus

ABSTRACT

Material handling apparatus for storing and retrieving loads, which is presettable at a first area for automatic transfer of a load between the first area and load supports of a second area and also between different load supports of the second area. The apparatus can be preset to select two positions in the second area at which load transfer is to be effected and will effect the transfer by movement directly from the first to the second selected positions regardless of their locations relative to the first area and independently of external commands once a transfer is initiated.

United States Patent Dunning et al.

[is] 3,701,442 1451 Oct 31,1972

1541 STORAGE AND RETRIEVAL APPARATUS [72] Inventors: Franklin W.Dunning, Painesville; Henry A. Gorjanc, Mentor, both of Ohio [73]Assignee: McNeil Corporation 22 Filed: Sept. 25, 1970 [21] Appl. No.:75,668

Related US. Application Data [63] Continuation of 'Ser. No. 769,444,Oct. 21, 1968, abandoned, which is 'a continuation of Ser. No. 470,380,July 8, 1965, abandoned;

[52] US. Cl ..'.....214/ 16. 4 A, 187/9, 187/26 [51] Int. Cl .,.B65gl/06 [58] Field of Search ..2l4/16.4 A

[56] References Cited UNITED STATES PATENTS 3,139,994 7/1964 Chasar.......214/16.4 A

3,313,427 4/1967 lnuzuka ..2l4/l6.l CB

FOREIGN PATENTS OR APPLICATIONS 1,368,184 6/1964 France "214/164 APrimary ExaminerGerald M. Forlenza Assistant Examiner-Raymond B. JohnsonAttorney-Watts, Hoffman, Fisher & Heinke 5 7 1 ABSTRACT Materialhandling apparatus for storing and retrieving loads, which ispr'esettable at a first area for automatic transfer of a load betweenthe first area and load supports of a second area and also betweendifferent load supports of the second area. The apparatus can be presetto select two positions in the second area at which load transfer is tobe effected and will effect the transfer by movement directly from thefirst to the second selected positions regardless of their locationsrelative to the first area and independently of external commands once atransfer is initiated.

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ATTORNEYS PATENIEflucransrz' SHEET 10 0F 1 1 N M W. 5 r Y RY P. M 5 mmm, 3W m 2 2 WWR mam 5 W TW 2 a c E0 CU m s m p u s a. a l x w e u a w sm F W D P @W H ER w 7 m m d J m M H w m 2 4 F C H R k n lx R l l K H m w4 M a 1 a 4 M w. m .1 R 4 H F. m w my M 4 M 2 a S 4 P 0L! RI K&|h Mll B2 2w M R T R i. i. a.. a 2 e P 9 M m m A. I A M n z w 5 u| 1 5 2 I c M mx N #4 R? m I; R f a 5 4 F 6 A S [7. U f .vlli 5 2 c F RLI MA 5 N. 5 c ka L .I! Q W. W M u. M. M M RIF R A 11 0/, w m W a 7 F m 4 0. 2 3 4 7 9 23 B 5 .M 5 5 5 5 A 5 w 5 w W 6 6 HENRY A. GORJANC BY WW g ATTORNEYSSTORAGE AND RETRIEVAL APPARATUS CROSSREFERENCE TO RELATED APPLICATIONS8, 1965, both of which were assigned to the assignee of the presentapplication and are now abandoned.

The invention relates to a material handling apparatus and moreparticularly to a material handling apparatus which is adapted toautomatically transfer loads between selected load supports.

The objectives of modern warehousing-type operations, which term is usedherein, includes all practices of providing for the temporary storageand retrieval of goods whether the goods are in the process ofmanufacture, completed products awaiting shipment, or are being storedfor any reason, is efficiency and reliability. Lack of efficiency andreliability can make a warehousing operation unsuccessful bycreatingproblems such as failure to deliver goods on schedule, storinggoods improperly causing time delays in locating them as well as makingit difficult to maintain an accurate inventory of the goods, etc. Tohelp overcome these problems automatic material handling apparatuseshave been utilized for storing and retrieving goods from storage areasaccording to planned programs. Different types of automatic warehousingapparatuses have been proposed. For the most part they. have rathersophisticated con trol mechanisms for accomplishing the. storing andretrieving operations and have much to be desired in efficiency as theyusually require unnecessary and time consuming movements of the loadcarrier to accomplish the storage and retrieval functions.

One of the principal objects of this invention is to provide a novel,efficient, reliable andsafe material handling apparatus whichautomatically transfers loads into and out of storage and which operateswith little or no lost motion in performing its programmed functions.

Another object of the present invention is the provision of a novelmaterial handling apparatus which is operable to transfer loads betweena dock area and preselected load supports arranged in bays and which iscontrolled in one sequence of operation to automatically transfer a loadfrom the dock area to a first preselected bay load support, movedirectly from the first load support to a second preselected bay loadsupport, remove a load from the second bay load and return the retrievedload to the dock area.

A further object of the present invention is the provision of a novelmaterial handling apparatus which is operable to transfer loads betweena dock area and preselected load supports and which is controlled in onesequence of operation to automatically retrieve a load from one of thebay load supports and to deposit same at a second bay load support. 1

A further object of the present invention is the provi-' sion of a newand improved material handling apparatus of the type referred to whereinthe controls therefor include add and subtract-type counter means.operable in response to the load carrier passing a predetermined numberof load supports to position the load carrier at a first preselectedload support in position to accomplish a load transfer thereat and tomove the load carrier from this position either to the dock area ordirectly to a second preselected load support in position to accomplisha load transfer thereat.

A further object of the present invention is the provision of a novelmaterial handling apparatus of the type referred to which is controlledby means responsive to completion of the load transfer at thepreselected bay load support to move the load carrier directly to thedock area or to a second bay load support.

A further object of the present invention is the provision of a novelmaterial handling apparatus of the type .referred to in which thecontrol means for'the load carrier include means for determining thedirection of movement required of said load carrier to move from a firstpreselected bay load support to the second 'preselectedbay load supportand to effect operation of and which includes a transfer unit for movingthe loads between the dock area and preselected bay load supportscharacterized by a trolley mounted on overhead tracks for horizontaltravel movement relativeto the vertical rows of load supports toposition the unit at a preselected station, elevator means mounted onthe trolley for vertical movement relative to the horizontal rows ofload supports, a load carrier movably mounted on the elevator andadapted to extend laterally therefrom into the preselected load support,reversible drive means for the trolley, elevator and load carrier, anauxiliary drive means for the elevator effective to move the tablevertically a slight distance relative to the load supporting surfaces ofthe load supports to effect transfer of loads between the load supportsand load carrier, and control means for the reversible drive means forthe trolley, elevator and load carrier effective toautomaticallyposition the load carrier at a first preselected loadsupport, extend the load carrier into the load support and operable toenergizethe auxiliary drive means for the elevator to move the loadcarrier vertically to effect a load transfer thereat, return the loadcarrier onto the elevator and to thereafter move the load carrier to thedock area or directly to a position in alignment with a secondpreselected load support and toeffect a load transfer thereat andthereafter to the dock area.

Another object of the present invention is the provision of a novel andimproved material handling apparatus of the type referred to in whichthe controls therefor include means preventing operation of the trolleyand elevator drive means when the load carrier is extended laterally ofthe elevator.

Another object of thepresent invention is the provision of a novel andimproved material handling apparatus of the type referred to in whichthe controls therefor include a safety means whichprevents opera tion ofthe load carrier drive means unless the load carrier is aligned with aload support.

A further object ofthe present invention is the provision of a novel andimproved material handling apparatus of the type referred to in whichthe controls therefor include safety means which permits actuation ofthe auxiliary elevator motor only when the load carrier is in one of itsextended positions.

A further object of the present invention .is the provision of a noveland improved material handling apparatus of the type referred to inwhich the trolley drive means include a multiple speed hydraulic motorwhich is controlled by means effective to operate the motor at highspeed until the transfer unit reaches a position immediately precedingthe selected load support at which time the controls are effective toshift the trolley drive means to slow speed operation for finalalignment of the transfer unit at the selected load support. I

Another object of the present invention. is the provision of a novel andimproved material handling apparatus of the type referred to in whichthe controls include an add and subtract counter means which is effectedto initiate deceleration of the trolley drive motor during the shiftfrom high to low speed.

A further object of the present invention is the provision of a new andimproved material handling I apparatus of the type referred to in whichthe drive means for the elevator include double acting, reciprocatingtype motors which are effective to drive the elevator through aplurality of cables or sprocket chain hereafter referred to as cablesattached to the elevator and which are arranged in such a manner thatthe elevator motor and the auxiliary elevator motor act to change theeffect of the length of the cables producing the elevator up and downmovement.

Another object of the present invention is the provision of a novel andimproved material handling apparatus effective to transfer loads betweena dock area and preselected load supports arranged in bays of horizontaland vertical rows and which includes a load carrier extendable fromoppositesides of the apparatus to pick up or deposit loads on oppositesides of the carrier and control means for extending the load carrierselectively to either side and when in the extended position to effectload pick up or deposit.

A further object of the present invention is the provision of a noveland improved material handling apparatus operable to transfer loadsbetween a dock area having load supports disposed in spaced opposingrelationship and load supports arranged in tiered horizontal andvertical rows in opposing bays, the bays and dock load supports arepositioned on opposite sides of the path of travel of a servicingtransfer unit and wherein the transfer unit has a load carrier movablelaterally to opposite sides of the unit and is controlled toautomatically pick up a load to be stored from either dock load supportand to subsequently move the load to a first preselected station whereinthe load carrier is moved laterally to either side of the unit into afirst preselected bay load support and vertically to deposit the loadtherein and the load carrier is moved to a second preselected bay loadsupport where the load carrier moves laterally and vertically to removea load therefrom and the carrier returns the retrieved load to the dockarea where the load carrier is selectively moved laterally into eitherdock load support and deposited thereon.

A further object of the present invention is the provision of a new andimproved load storage apparatus of the type referred to wherein thecontrols are effective to move the carrier load supporting means toeither bay or bays to reach the first and second preselected loadsupports.

Further objects and advantages of the present invention will be apparentfrom the following detailed description made with reference to theaccompanying drawings, in which:

FIG. 1 is a perspective view of the material handling apparatus of thepresent invention illustrating the transfer unit at the idle station;

FIG. 2 is a side elevation of the transfer unit shown in FIG. 1;

FIG. 3 is a perspective view of the load carrier of the transfer unitillustrating the load carrier in its left position;

FIG. 4 is a plan diagrammatic view ofa portion of the transfer unitshowing the trolley drive means;

FIG. 5 is a fragmentary side elevation of a portion of the trolleyassembly illustrating the arrangement of switches and photocell units;

FIG. 6 is a side elevation of a portion of the main elevator motor EMillustrating the hoist counting and elevator position switches;

FIG. 7 is a diagrammatic plan view ofthe load carrier illustrating thearrangement of switches actuated thereby;

FIG. 8 is a side elevation of the auxiliary elevator motor EM showingthe switch arrangements therefor;

FIG. 9 is a side elevation somewhat diagrammatic showing the transferunit and related load supports and the numbering system used to identifythe various storage area load supports;

FIG. 10 is a schematic representation of the hydraulic controls of thepresent invention; and

FIGS. 11 through 16 form a continuous electrical circuit diagram ofautomatic controls of the present invention.

- Referring to the drawing in which a preferredembodiment of theinvention is disclosed and in particular to FIG. 1 which discloses amaterial handling mechanism comprising a load transfer unit TU supportedfor movement along an overhead trackway TW extending between a first ordock area at which right and left dock load supports RDLS and LDLS arelocated and right and left bays RB and LB of tiered bay load supportsRDLS and LDLS, respectively, located in a second or storage area S. Thetransfer unit TU comprises a trolley assembly TA movable along thetrackway TW, a vertical mast assembly MA depending from the trolleyassembly TA, an elevator assembly EA movable along the mast assembly MAand a load carrier LC supported on or forming part of the elevatorassembly EA and movable to opposite sides of the mast assembly forpicking up and/or depositing loads at the dock load supports and the bayload supports. The right bay load supports RBLS and the left bay loadsupports LBLS are arranged in horizontal and vertical rows in the rightand left bays RB and LB, respectively, which are aligned in spacedopposing relationship in the second or storage area S. The storage loadsupports RBLS and LBLS and dock load supports RDLS and LDLS areoppositely spaced a sufficient distance to permit movement of loadcarrier LC therebetween to service at any one station, all load supportson opposite sides of the mast assembly which are in alignment with theload carrier LC. For example, when the load transfer unit is in dockarea D, which is its position illustrated in FIG. 1, it can serviceeither the right or left dock load support (the left dock load supportLDLS is shown in FIG. 9). On the other hand, when the load transfer unitTU ispositioned at a selected station in storage area S, it can serviceall load supports RBLS and LBLS included in thetwo opposed vertical rowsat the selected station.

Loads to be stored in the storage area S are delivered to the dock loadsupports by any suitable type of con veying mechanism and oncedepositedthereon are in position to be engaged by the load carrier LC extendablelaterally to opposite sides of the mast assembly. The mast properincludes two spaced I-beams 26, 28 connected at their upper ends totrolley assembly TA and are connected at their low ends and have guidemembers 30 extending laterally from their lower ends which slidablyengage guideways 32 secured to the floor or like support of the area tobe serviced by the material handling apparatus. The ends of laterallyextending guide members 30 slidably engage upstanding flanges on theguideway 32 and function to steady the depending mast. The elevatorframe member 22 is secured in guided relationship on mast assembly MA byeight guide rollers 34 carried by the elevator and in engagement withopposite sides of the base of the I-beams 26, 28. The rollers stabilizethe elevator against tipping or shifting movement relative to the mastin one direction. Four adjustable guide rollers 36 also carried by theelevator engage and ride on two edges of each I-beam and function tosteady the elevator against tipping or rocking between the I-beams 26,28.

The load carrier LC shown is especially designed for handling palletizedloads by the engagement of its upper surface underneath the palletduring the transfer operation. It is to be understood, however, that anytype of load carrier can be substituted for the one shown and that theapparatus of the invention is intended to handle all types ofloads. Theload carrier LC is supported for movement to its lateral positions onopposite sides of the mast on slide 38 which in turn is supported forlike movement on members 39fixedly carried by the base 40 of elevatorframe member 22. The members 39 have secured thereto a plurality ofguide rollers 42 which guidingly engage rollerways 44 in the movableslide 38 as clearly illustrated in FIG. 3. The load carrier LC ismounted for sliding movement relative to movable slide 38 on a pluralityof guide rollers 46 carried by slide 38 and which engage the undersideof load carrier LC. The load carrier is supported by members 39 andslide 38 for lateral movement from a center position on the elevator toarbitrarily designated right and left positions on oppositesides of themast assembly as viewed in FIG. 1.

The load carrier is driven from its center position to the right or theleft by means of a double acting reciprocating hydraulic load carriermotor means LM supported on elevator base 40 and has a rack 49 (FIG.mounted on the free end of piston rod 48 which is supported to engage apinion 51 secured to a rotatable shaft 50 upstanding from elevator base40 and which carries on the upper end thereof a drive sprocket 52.Reciprocation of piston rod 48 rotates sprocket 52 in clockwise andcounterclockwise directions, as indicated by the arrows on the sprocket(FIG. 3), and is Chain 62 extends from anchor 70' drivingly connected toopposite ends of movable slide 38 by means of a chain 54 which issecured at one end to one end of movable slide 38 at 56, and extendstherefrom around drive sprocket 52 and around an idler sprocket assembly58 upstanding from elevator base 40 and is anchored at its other end tothe opposite end of slide 38 at 5,9. Reciprocation 48 in the oppositedirection rotates'pinion 52 in the counterclockwise direction and movesslide 38 through chain 54 to the left or towards the upper edge of thedrawing as viewed in FIG. 3. Load carrier LC is moved by slide 38through chains 60 and 62 at twice the speed that motor LM moves slide 38so that the load carrier LC and slide 38 arrive at their extremepositions of movement simultaneously. Since load carrier LC must movetwice as far as slide 38 it accordingly moves twice as fast to enablethe slide and load carrier to reach their limits of travelsimultaneously. Chain 60 imparts movement to load carrier LC in thedirection of arrow 62 on the load carrier in FIG. 3 which accomplishesmovement of the load carrier from its left position to its centerposition and from its center position to its right position. One end-ofchain 60 is anchored to one end of the load carrier at 64 and extendstherefrom forming an upper reach which passes over and around an idlersprocket secured to one end of slide 38 and extends therefrom forming alower reach which is anchored to elevator base 40 at 66. A portion ofthe upper reach of chain 60 has been broken away in FIG. 3 to expose aportion of the lower reach thereof and anchor 66. Chain 62 impartsmovement to the load carrier in the direction of arrow 68, whichaccomplishes movement from its right position to its center position andfrom its center position to its left position. Chain 62is anchored at toone end of the load carrier opposite the end to which chain 60 isanchored and the outer end of chain 62 is anchored at 72 onthe mountingfor motor LM. over and around an idler sprocket 74 secured on an end ofslide 38 opposite the end to which the sprocket for chain 60 is securedand extends therefrom as a lower reach to anchor 72. From the foregoingarrangement of drive means, it is apparent that the load carrier ismovedfrom its center position on the elevator to its lateral left andright positions on opposite sides of the elevator base by hydraulicmotor LM and chains 54, 60 and 62 and in so moving to and from thesepositions the load carrier LC moves at twice the speed of and twice asfar as the movable slide 38 so that that slide 38 and load carrier LCreach their limits of travel at the same time.

The elevator assembly EA and attached load carrier LC are movedvertically along mast MA by means of a double acting, reciprocatinghydraulic motor EM which controls cables 76, 78 and 810; cables 76 and78 are anchored to the free end of a piston rod 82 of a double acting,AEM, the function of which will be explained hereafter. and extendstherefrom under and around the outer pulley or sheaves 84 and 86attached to the free end of piston rod 88 of hydraulic motor EM by meansof a sheave or pulley block 90 and up to, over and around a spaced pairof sheaves 90 and 92 located assembly TA adjacent beams 26 and 28, downalong beam 28 and are anchored to one side of the elevator assembly EAat 94 as shown in FIG. 1; the cable is of the piston rod reciprocatingauxiliary elevator motor on the trolley connected at one end to the endof piston rod 82 of auxiliary elevator motor AEM and extends around anintermediate pulley 96 supported by sheave block 90, up to, over andaround sheave 98 supported on the trolley adjacent I-beam 26 of mastassembly MA, down along beam 26 and is anchored to the other side of theelevator assembly EA opposite the side to which cables 76 and 78 areanchored. Assuming that the elevator is in its idle or rest positionwhich is the position illustrated in FIG. 1 of the drawings, and thesheave block assembly 90 and piston rod 88 of motor EM are likewise intheir position illustrated therein, application of fluid pressure to thepiston rod end of the cylinder of motor EM moves the piston rod 88 andattached sheave assembly 90 downward toward the bottom of the cylinderexerting a force on cables 76, 78, 80 which will in turn move theelevator EA upward along mast MA eventually, if not interrupted, to theposition illustrated in FIG. 2. The elevator is lowered by reversingthis operation which moves piston rod 88 upward toward its positionillustrated in FIG. 1 which will slack cables 76, 78, and 80, which istaken up by the elevator as it moves downward along mast assembly MA.

Elevator motor EM, by changing the effective lengths of cables 76, 78,80 between pulleys 90, 92 and 98 and elevator EA, moves the elevatorvertically relative to the horizontal rows of storage load supports RBLSand LBLS and the dock load supports RDLS and LDLS to position the loadcarrier relative thereto so that it can move laterally into the loadsupports without interference with loads positioned on the load supportswhere a load is to be transferred onto the load carrier or a load on theload carrier does not interfere with the load support structure where aload is to be transferred onto the load supports. The load transfer fromload carrier LC onto the load supports of the dock and storage area isaccomplished by positioning load supporting surface of load carrier LCin a load support adjacent to and above the upper surface of the loadsupports which is to receive the load and moving the elevator down asmall distance, such as two or three inches, which movement transfersthe load from the load carrier onto the load supporting surface of theload supports. To transfer a load from the load supports onto the loadcarrier the empty load carrier is extended into the load support belowthe bottom 'surface of the pallet supported on the load support andmoved upward an incremental distance which transfers the load from theload supports onto the load carrier. After either of the described loadtransfers between the load carrier and a load support, motor LM isactuated to return the load carrier to its center position either emptyor full depending upon the type of transfer accomplished at the loadsupport.

The incremental vertical movement of the elevator when the load carrieris extended into a selected load support is accomplished by theauxiliary elevator hydraulic motor AEM which, when actuated, moves theends of cables 76, 78 and 80 anchored to the end of piston rod 82 asufficient distance to produce the required vertical elevator movementto raise or lower the load carrier relative to the load support.Providing independent motors arranged in the above described manner toaccomplish the incremental elevator movements relieves the large mainelevator motor EM from producing the small vertical transfer movementand permits more positive safety control of the elevator which is veryadvantageous in automatic material handling equipment which will becomeapparent from the controls disclosed in FIGS. 11 to 16. For example, thecontrols render main elevator motor EM inoperative whenever load carrierLC leaves its center position on the elevator which eliminates damage tothe load carrier, adjacent load supports, and loads which might occurwhere elevator motor EM is required to produce both movements and wherethe controls due to ma]- function move the load carrier a greatervertical distance than necessary during transfer operations causing acollison. Auxiliary motor AEM is operable only when the carrier is inits right and left positions and the maximum distance this motor canmove the elevator is so small that, in the event of malfunction of thecontrols, no damage to the load support would occur. This control is notpossible in cases where one motor has to provide both elevatormovements. Also, for motor EM to handle both movements, additional cyclecontrols would have to be provided to control the type of movement to beperformed by the motor at a particular time. Of course, the moreintricate the controls, the more chance there is for malfunction.

Further, by providing hydraulic jack-type elevator motors EM and AEMhaving fixed stokes which determine the maximum extent of elevatormovement apart from any controls therefor, eliminates the need for avertical overtravel control for the elevator.

The trolley assembly TA is movably guided along trackway TW by trolleywheels 100, 100A supported in' four truck assemblies 102 adjacent thecorners of the trolley framework 104. Each truck 102 supports fourwheels; two of the wheels engage the horizontal flange of the trackwayson one side of the vertical web and the other two wheels engage thehorizontal flange on the other side of the vertical web. The transferunit travel movement is provided by motor TM (FIG. 4) supported on thetrolley frame 104 and which drives trolley drive wheels 100A throughspeed reducers, shafts and gears 106 which are journalled on the sameshaft as wheels 100A or are formed integral therewith and imparts adriving movement to the wheels to move the load carrier along thetrackwaysTW. The drive is not disclosed in detail herein and anysuitable drive mechanism can be employed and by way of example, thedrive for wheels 100A can be of the general type disclosed in U. S. Pat.to Cotesworth, No. 2,985,l I3, issued May 23,1961.

The transfer unit TU in the course of transferring loads operates froman idle station which is the unit position illustrated in FIG. 1. Whenthe unit is in this station, the trolley, elevator, and load carrier arein their so called idle positions wherein trolley assembly TA ispositioned to dispose elevator assembly EA in vertical alignment withthe dock load supports RDLS and LDLS, the elevator is disposed in itsdown or lowermost position on mast MA, and load carrier LC is in itscenter, low position aligned to move into either dock load support totransfer a load onto the load carrier.

To store a load resting on load support RDLS in a selected one of thestorage load supports RBLS or LBLS, assuming the stacker crane ortrolley assembly TA, elevator assembly EA, and load carrier LC are intheir idle positions at the idle station, as heretofore described, loadcarrier motor LM is actuated to move the load carrier laterally intodock load support RDLS and beneath the pallet supported on one of thedock load supports. Auxiliary elevator motor AEM is actuated and movesthe load carrier up the required incre' mental distance to transfer theload from the dock load onto the load carrier. Load carrier motor LM isreversed to move load carrier to its center position on the elevator inits high position due to the upward movement of the elevator by theauxiliary hoist motor AEM. Hydraulic trolley drive motor TM moo movesthe transfer unit TU along trackway TW to the selected carrier stationin storage area S whereat the elevator is in vertical alignment with twoopposed vertical rows of load supports in the left and right bays, whichrows include the load support selected to receive the load from the loadcarrier. The elevator assembly EA is moved by main elevator motor EMrelative to the horizontal rows of load supports to its level whereinthe load carrier is in alignment with a selected load support. Motor LMis actuated to drive the load carrier laterally into the selected loadsupport. The load is transferred ontothe load support by downwardmovement of the load carrier by auxiliary elevator motor AEM, placing itin its low position. The load carrier is returned to its center position on the elevator by reversing operation of motor LM after which thetrolley drive motor TM and the elevator motor EM return them to theiridle positions at the idle station at dock D to await further operation.The travel motor TM and elevator 'motor EM are operated simultaneouslyso that the elevator and trolley move to their respective positionssimultaneously which reduces the time required for the transfer unit toaccomplish a cycle of operation.

Retrieving a load from the storage area and transferring it onto one ofthe dock load supports is accomplished in generally the same mannerexcept the sequence of operation of the load carrier, elevator andtrolley are different. The elevator is moved by elevator motor EMrelative to the horizontal rows of load supports as the trolley assemblyTA moves from the idle station to the selected station which positionthe load carrier which is in its low position, in alignment with andbelow the load on the selected storage load support. The load carrier isextended by motor LM to a position beneath the load to be retrieved andthe load carrier is then moved upward by the auxiliary motor AEMtransferring the load from the storage load support onto the loadcarrier. The load carrier is returned to its center position on theelevator and the elevator and trolley move by motors EM and TM to theiridle positions at the idle station in dock area. The load carrier is notin its high position due to the upward movement thereof during transferand lateral movement to the left or right by motor LM positions the loadover the receiving dock load support. The load transfer is accomplishedby downward movement of the load carrier by auxiliary motor AEM whichdeposits the load on the selected load support. The load carrier is thenreturned to its center position on the elevator in its low position andthe crane is ready to perform another cycle of operation.

The power plant as well as the controls for operating the power plantare carried entirely on the transfer unit so that the only externalpower needed to operate the carrier automatically is power forenergizing the controls which is supplied by a plurality of power linesL1, L2 and L3 disposed along one of the trackways TW and which areconnected to the control circuits of the carrier by means of powercollectors L-lC, L-2C, L-3C shown. diagrammatically in FIG. 11. Thedrive motors TM, EM, AEMand LM are hydraulically operated and arecontrolled by solenoid actuated valves which are selectively energizedand de-energized by relays which in turn are operated by switches,photoelectric cell units and counters which sequentially make andbreakcircuits, according to the setting of the control elements.

HYDRAULIC SYSTEM The hydraulic circuit fro controlling the motors isshown in FIG. 10 and will be hereinafter described in relation to themanner in which they affect operation of the motors.

The valves are illustrated in FIG. 10 in their respective setting theyassume when their operating solenoids are not energized.

The hydraulic system includes pumps P1 and P2 which are driven by anelectric pump drive motor PM. Pump P1, which has a higher volume thanpump P2,

supplies fluid under pressure to elevator motor EM and pump P2 suppliesfluid under pressure to the trolley assembly drive motor TM, the loadcarrier drive motor LM, and the auxiliary elevator motor AEM. The valvesin FIG. 10 are diagrammatic representations of well known and commercialavailable valves and ac cordingly will not be described structurally.Suffice it to say that the valves settings are changed by solenoids andsprings. The valves are spring biased into one position and are movedinto their other settings by the solenoids against the bias of thesprings. The sections of the multiple section valves are identified bythe letter S with'a numeral thereafter. Section S1 of each multiplesection valve indicates the section which is moved into communicationwith the associated circuit by the springs when the solenoids arede-energized. Sections S2 and S3 are moved into communication with thecircuit by the solenoids against the bias of the springs.

In describing the motor control operation, it is assumed that theelectrical pump motor PM is actuated, driving pumps P1 and P2.

TROLLEY ASSEMBLY MOVEMENT The transfer unit forward travel isaccomplished by driving motor TM in a clockwise direction, indicated .byan arrow on motor TM in FIG. 10. To drive motor TM in clockwisedirection at high speed, solenoid A of valve V1 is energized to shiftvalve section S2 into com- The slow speed operation of motor TM isaccomplished by de-energizing solenoid C, causing section S1 of valve V2to be spring shifted into the circuit establishing fluid flow betweenlines H6 and H8 and through a restriction valve V3 to sump. Therestriction valve V3creates a dampening effect on motor TM causing it tooperate at slow speed.

The transfer unit forward travel motion is stopped by de-energizingsolenoid A of valve V1 which spring shifts valve section S] into thecircuit blocking fluid flow to motor TM. Relief valve V4 provides forgradual stopping of motor TM when valve V1 is shifted to block flow tothe motor to prevent skidding of trolley wheels 100A. When valve V1 isshifted to blocking position the momentum of the load carrier causescontinued rotation of motor TM in the clockwise direction which buildsup the pressure in outlet line H4 to a point exceeding the pressure ininlet line H3. Gradual release of this pressure to the normal operatingline pressure provides for gradual stopping of the motor and isaccomplished by providing relief valve V4 with a relief settingslightlyabove the normal operating line pressure. Build up of pressurein line H4 above operating line pressure causes the pressure in line H4to be relieved through the check valve in line H9, through the valve V4which is now open, line H10 to sump. Fluid will flow through thiscircuit until the pressure in line H4 equals the relief setting of valveV4 at which time valve V4 will close due to the action of its spring.Opening and closing of relief valve V4continues until motor TM comes toa gradual stop. This stopping action occurs when the unit is stopping ata selected load support while traveling slow and also when the unitcomes to a stop from high speed during an emergency such as powerfailure.

To drive the transfer unit from the storage area to the dock area athigh speed, motor TM is driven in counterclockwise direction byenergization of solenoid B shifting section S3 of valve V1 into circuitto provide fluid communication between lines H2 and H5 and between linesH3 and H6. This valve setting directs the fluid under pressure from pumpP2 to the opposite side of the motor TM throughlines H1, H2, valvesection S3, lines H5 and H4, and the fluid is returned from the motor TMthrough line H3, section S3 of valve V1, line H6, section S2 of valveV2, line H7 to sump.

The reverse travel slow speed drive of motor TM is accomplished in thesame manner as explained in connection with the forward travel operationof motor TM.

The reverse travel movement is stopped by de-energizing solenoid Bcausing section S1 of valve V1 to spring shift into blocking position inthe circuit. Valve V4 is effective to bring motor TM to a gradual stopafter section 51 of valve V1 is shifted into blocking position in thesame manner as explained in connection with the gradual stopping ofmotor TM when moving in the forward direction except that the pressureis relieved from line H3 which is the outlet line from motor TM whenrotating in the counterclockwise direction.

DECELERATION OF TROLLEY ASSEMBLY MOTOR TM The trolley drive motor TM isdecelerated when shifting from high speed to low speed to preventskidding of the trolley wheels 100A during the speed transition. This isaccomplished, in part, by a remote solenoid valve V5 which remotelycontrols the relief setting of relief valve V6 which in turn controlsthe fluid pressure output of pump P2. Valve V6 has two relief settings:one setting is higher than the desired operating line pressure of lineH1 and the other setting is at approximately zero psi. During high andslow speed operation of motor TM, solenoid J is energized to shiftsection S2 of valve V5 into blocking relationship in the pilot line H11which sets relief valve V6 at its high relief setting. Duringdeceleration of motor TM, solenoid J is de-energized by a timing relaycausing section S1 of remote solenoid valve V5 to spring shift providingcommunication between pilot line H11 and sump which sets relief valve V6at its zero psi setting which in turn substantially reduces the pressurein lines H1, H2 and H3. Solenoid J remains de-energized until motor TMdecelerates sufficiently. The-momentum of the transfer unit drives motorTM and which in effect makes motor TM function as a pump drawing fluidup through lines H1, H2, valve V1 and line H3 and which is returnedthrough lines H4, H5, valve V1, line H6, valve V2, lines H8 torestriction valve V3 to sump. When the pressure is reduced in line H1 byoperation of remote solenoid valve V5, a second remote valve V7controlling the remote relief setting of valve V4 becomes operative dueto sensing the lower pressure in lines H1 and H32 and lowers the settingof valve V4 from a relief setting higher than the main line pressure inline H3, assuming a clockwise driving rotation of motor TM, to asubstantially lower relief setting so that the fluid leaving the outletside of motor TM flows through line H9, through relief valve V4 to lineH10 to sump. This state of deceleration continues until the timing relaycontrolling solenoid J of remote solenoid valve V5 re-energizes solenoid.1 which shifts valve V5 to block the flow through pilot line H11thereby changing the relief setting of valve V6 to the higher reliefsetting which in turn establishes normaloperating pressure in lines'Hl,H2 and H3 to the motor TM and the motor operates a slow speed due todampening effect produced by restriction valve V3. When normal operatingline pressure exists in lines H1 and H32 remote relief valve V7 isineffective and relief valve V4 operates at its normal relief settingwhich is slightly higher than the normal operating pressure in thelines. The heretofore described deceleration thus controls motor TM sothat the transition from the high speed setting to the low speed settingis gradual and prevents undesirable skidding of trolley wheels A whichwould otherwise occur in the absence of valves V4, V7, V5 and V6.

ELEVATOR ASSEMBLY EA MOVEMENT Upward movement of the elevator assemblyis accomplished by pump Pl providing fluid under pressure to the upperor piston rod side of motor EM and which is returned to sump from thelower end of the cylinder of motor EM. The pressure output of pump P1 iscontrolled by relief valve V13. The hoisting action is controlled by thesetting of valve V8 which is a three position valve, shown with itssection S1 blocking fluid'flow to motor EM and directing the fluiddelivered thereto by pump P1 to the sump. Valve V8 is shifted byenergization of solenoid E so that section S3 thereof controls the fluidflow to motor Em through lines H12 to H13. The fluid circuit begins withpump P1 which directs fluid under pressure throughline H12, section S3of valve V8, line H13, check valves V10, V11 to motor EM. The fluid isreturned from the lower end of the cylinder through line H15, valve V8,line H16 to sump. The upward movement of motor EM is stopped byde-energizing solenoid E causing section S1 of valve V8 to spring shiftto put the output of the pump to sump.

The elevator EA is lowered by moving the piston rod of motor EM out ofthe cylinder and is accomplished by energization of solenoid D whichshifts valve V8 so that section S2 thereof provides fluid communicationbetween lines H12 and H15 and the fluid is returned from the. upper endof the cylinder of motor EM through restriction valve V9, check valve Vheld open by pressure in pilot line H17, lines H13, valve V8, line H16to the sump. T his arrangement provides for controlled lowering of theelevator EA. If pressure drops in line H15, check valve V10 will not beheld open by pressure in pilot line H17 and consequently will block flowin line H13 until the pressure in line H builds up.

LOAD CARRIER MOVEMENTS The load carrier LC is moved into three.positions by motor LM. The positions are the center position on theelevator illustrated in FIG. 1, the right position where the table isextended laterally of the mast MA to the right as viewed from FIG. 1,and the third position of adjustment is the left position where the loadcarrier is extended laterally to the left of the mast MA as illustratedin FIG. 3. To move the load carrier from its center position to itsright position, the three position valve V14 is shifted by energizationof solenoid I so that section S2 establishes communication between pumpP2 and the piston rod end of motor LM by a circuit from pump P2, throughline H1 to line H19, through restriction valve V12, through section S2of valve 14, line H20 to motor LM. The fluid is returned from theopposite end of the cylinder of motor LM through line H22, valve V14,line H24, relief valve V16, line H to sump. This circuit is maintaineduntil the piston is moved from its centered position in the cylinder,which is the position illustrated in FIG. 10, to its extreme leftposition in the cylinder at which time solenoid I is deenergized andvalve V14 is spring shifted to a position where section S1 blocks flow.When the motor LM is in the described position load carrier LC is in itsright position.

The load carrier is moved from its right position to its center positionon the elevator by energization of solenoid H which shifts section S3 ofvalve 14 into the circuit to establish communication between lines H19and H22 to deliver fluid under pressure to the left side of the cylinderof motor LM to drive the piston to the centered position in thecylinder. The fluid is returned from the cylinder through line H20,valve V14, line H24, relief valve V16, line H25 to the sump. When thepiston rod reaches its centered position in the cylinder at which timeload carrier LC is in its center position, solenoid H is de-energizedand valve V14 is spring shifted so that section S1 again blocks fluidflow.

To move the load carrier from its center position on the elevator to itsleft position, solenoid H is again energized to deliver fluid to theleft end of the cylinder of motor LM to drive the piston rod from itscenter position in the cylinder to the right position'therein whichaction effects movement of the load carrier to its left position asillustrated in FIG. 3. When the load carrier reaches its left positionsolenoid H is de-energized and the valve V14 is spring centered withsection S1 blocking flow through the valve. The load carrier is returnedfrom its left position to its center position by energization ofsolenoid I which shifts section S2 of the valve to establish flowthrough lines H19 and H20 to the right side of the cylinder of motor LMdriving the piston rod from its position adjacent the right end of thecylinder towards the center and when it arrives in the center positionat which time load carrier is at its center position, the solenoid I isde-energized and section S1 of the valve V14. blocks flow. The operatingspeed of motor LM is controlled at all times by adjustable restrictionvalve V12 in conjunction with relief valve V16 which provides backpressure on the outlet side of the motor.

The load carrier when in one of its extended positions, is movedvertically by elevator EA by means of auxiliary elevator motor AEM toaccomplish the load transfer between the load carrier and load supports.To

effect lowering movement of the load carrier to its low position whichmovement transfers a load onto a load support, valve V18, which is athree-section valve, is shifted by energization of solenoid G to placesection 52 of valve V18 in circuit to direct fluid under pressure frompump P2 through lines H1 and H27, section S2 of valve V18, line H28, tothe upper end of the cylinder of motor AEM. The fluid is returned fromthe lower end of the cylinder through line H29, restriction valve V19,check valve V20, held open by fluid pressure in pilot line H32, lineH30, valve V18, line H31 to the sump. Valves V19, V20 and V21 controlthe incremental lowering of the elevator similar to the manner in whichvalves V9, V10 and V1 1 control movement of elevator motor EM. Valve V19provides a restricted orifice and valve V20 is a check valve whichblocks flow of fluid from line H29 to line H30 until the pressure buildsup in line H28 providing for controlled lowering of elevator EA. This,of course, is necessitated to counteract the effect of gravity on theelevator during downward elevator movement. When the load carrier hasbeen lowered a sufficient distance to transfer the load onto the loadsupport, solenoid G is deenergized and valve V18 is spring centered sothat section S1 thereof blocks flow to lines H28 and H30. To accomplishupward movement of the load carrier in the course of transferring a loadfrom the load support onto the load carrier, valve V18 is shifted byenergization of solenoid F shifting section S3 of valve V18 in circuitwhich establishes fluid pressurein line H30, which delivers fluid underpressure to the piston rod end of the cylinder of motor AEM via checkvalve V20 and V21 and moves the piston rod upward along with the cableattached thereto which effects raising of the elevator EA and loadcarrier LC. The fluid is returned from the upper end of the cylinderthrough line H28, valve V18, line H31 to the sump. After sufficientupward movement of the load carrier is accomplished, solenoid F isde-energized and valve V18 is spring-centered so that section S1 thereofblocks fluid flow therethrough.

1.5 To obtain travel, hoisting and load carrier movements there must benormal operating pressure maintained in line H1 which is accomplished byenergization of solenoid J of remote solenoid valve V5 which in turnallows relief valve V6 to operate at its pressure setting.

Automatic operation of the load carrier is provided by the selectiveenergization and de-energization of the solenoids which in turn controloperation of the valves.

AUTOMATIC CONTROL OF THE TRANSFER UNIT TU The controls will be bestunderstood by a description of three automatic cycles of operations ofthe load carrier in the course of storing and retrieving loads. Thethree exemplary cycles of operation are an into storage cycle, and outof storage cycle", and a dual command cycle. The into storage cycleinvolves automatically moving the load carrier selectively to its rightor left position, depending on which dock load support is supporting theload, to pick up a load which has been previously deposited on the dockload support and to thereafter convey the load to a preselected storageload support in the storage area which is to receive and store the load.The load carrier is aligned with the selected storage load support,extended into the load support, moved down to transfer the load onto thestorage load support, and returned to its center position and thetransfer unit returns to its idle station at the dock area.

The out of storage cycle involves moving the transfer unit from itsposition at the idle station, illustrated in FIG. 1, into the storagearea S and aligning the load carrier with a preselected storage loadsupport in which the load to be retrieved is stored. The load carrier isthen moved laterally into the selected load support, upwards to transferthe load onto the carrier, laterally to its center position on theelevator and the transfer unit returns to the idle station where theload carrier is extended either to the right or to the left dependingupon which dock load supports is to receive the load, lowered totransfer the load onto the selected dock load support and returned toits center position.

The dual command cycle of operation of the crane combines the previouslydescribed into storage cycle" and out of storage cycle and involves forexample,

first controlling the unit to perform the into storage cycle and uponcompletion of the load transfer into a selected storage load support,the unit moves directly to a second preselected load support instead ofreturning to the idle station. When the crane is properly aligned at thesecond preselected storage load support, it is operated to perform theremainder of the out of storage cycle" in the same manner ashereinbefore described.

The dual command cycle also provides for a so called in storagetransfer. which includes first controlling the transfer unit to performthe out of storage cycle and on completion of transfer of the retrievedload onto the load carrier, the transfer unit moves directly to a secondpreselected storage load support. When the crane is properly aligned atthe second preselected load support, the unit is controlled to performthe remainder of the into storage cycle as heretofore explained. Beforeconsidering the circuit diagrams in FIGS. 11 through 16 in detail, theimportant relays will be identified along with a brief description oftheir function. The forward travel movement of the transfer unit, i.e.,the direction of unit movement in moving from the dock area D to thestorage area S, is controlled primarily by forward travel timer relayZTR (line 35, FIG. 14) and forward travel relay 15R (line 34, FIG. 14),which set up various circuits necessary to accomplish the forward cranemovement including energizing solenoid A (line 70, FIG. 16) of valve V1.to operate motor TM in the clockwise direction. The high speedoperation of motor TM is controlled by high speed relay 9TR (line 16,FIG. 12) which effects energization and de-energization of solenoid C ofvalve V2 in addition to initiating deceleration of motor TM during thespeed transition from high to slow speed.

A travel add-subtract type counter, or stepping switch, (lines 16, 17,19, 20, FIGS. 12 and 13) controls shifting of motor TM from high toslow. speed during forward or reverse travel when the unit arrives at aposition just preceding the station of its address. The counter orstepping switch, includes a plurality of wafers which are stepped in aclockwise or counterclockwise direction, depending upon whether the unitis moving in the forward direction in which case the counter discs areindexed in a clockwise direction, as viewed in FIGS. 12 and 13, or thereverse direction in which case the wafers are indexed in acounterclockwise direction so that the position of the transfer unit atany time is correctly indicated electrically by the wafers of thecounter or stepping switch. The travel wafers are'indicatedschematically in FIGS. 12 and 13 as SSWU-A, SSWT-A, SSWU-B and SSWT-B.The letter U in the reference character indicates that the disc is aunits counter and the letter T indicates that the disc is a tenscounter. The A suffix indicates that the counter operates during travelwhere one of the single cycles are being performed or to the firstaddress where a dual command is to be performed and the B suffixindicates the counter wafer operates during crane travel from the firstaddress to the second address where a dual command cycle is to beperformed by the unit.

Associated with each of the counter wafers or discs is a selector discinto which the address or addresses are set by rotary wheels located onthe front of control panel 115. The selector switches are identified asSELU-A, SELT-A, SELU-B and SELT-B corresponding respectively to thecounter switches SSWU-A, SSWT-A, SSWU-B, SSWT-B. Hence each of thestepping wafers of the counters have associated therewith a manuallysettable selector switch which cooperates with its associated wafer tomake and break circuits to control various relays in the circuit. Thestepping wafers SSWU-A, SSWT-A, SSWU-B, SSWT-B have disposed around thecircumference thereof 12 conductor points, 10 of which are used in thepreferred embodiment of the invention, which are spaced therearound inthe hourly positions comparing each of the stepping discs with the faceof a clock. Each of these points are connected electrically to thecorresponding conductor points on the associated selector switch. Thestepping wafer conductor points are connected electrically to the powerlines through the wafer. Each stepping wafer has a cut out portion ornotch which breaks the electrical connection through a point inalignment with the notch. Hence each travel

1. A material handling apparatus for moving loads between load supportmeans that form a dock area or home station and a plurality of storageareas arranged in horizontal and vertical rows, comprising: a loadtransfer unit movable horizontally and vertically along a path adjacentsaid storage areas and dock area and including a horizontally movabletrolley assembly, a first member carried by said trolley assembly tosupport a load, means supporting said first member to provide movementthereof laterally of the path of the load transfer unit and verticallyto effect load transfer between the said member and said load supportmeans of the storage area or dock area, drive means to move said trolleyassembly and load transfer unit and first member along said pathadjacent said areas and means to move said first member laterally of thepath, two vertically spaced fluid motors having relatively reciprocatingpiston and cylinder elements carried by said trolley assembly and acable extending from the means supporting said first member secured to areciprocating element of one of said fluid motors and extending about aRotary member connected to a reciprocating element of the other of saidfluid motors, one of said fluid motors operable to move the supportingmeans for said first member vertically between load support means andthe other serving as an auxiliary drive motor operable to move the firstmember an incremental distance vertically relative to said trolleyassembly to effect a load transfer, and means to control the movementand operation of the load transfer unit independently of externalcommands once the unit leaves the dock area, said means consisting ofelectrical circuit means operable to control movement of said firstmember vertically and horizontally concurrently, to control movement ofsaid first member laterally, and to render said drive means for saidunit and first member inoperable when the first member is movedlaterally of the path of the load transfer unit, said control meansincluding first means presettable prior to movement of the unit from thefirst area to control the drive means to move said transfer unit andfirst member from the dock area to a position adjacent a firstpreselected storage area and to move said first member laterally of thepath to a first position in the first preselected storage area inalignment with load support means and to subsequently effect a loadtransfer therebetween, second means presettable prior to movement of theunit from the first area to control the drive means subsequent to saidload transfer to move the first member directly from said firstpreselected storage area to a second storage area in alignment with loadsupport means thereof regardless of the locations of said first andsecond storage areas and to effect a load transfer at said secondstorage area, said first and second presettable control means includingfirst counter means for counting said vertical rows of storage areas andcontrolling the drive means to position said transfer unit at thevertical rows of first and second preselected areas, second countermeans for counting said horizontal rows of storage areas and controllingthe drive means to position said first member at first and secondpreselected storage areas, and means to change the speed at which thetransfer unit is moved from a high speed to a lower speed operation inresponse to the counting of a predetermined number of storage areas,sensing means carried by said load transfer unit for detecting changesin the vertical location and horizontal location of the first member toactuate said counter means controlling the operation of said motormeans, and said control means further including means for determiningthe direction of movement required to move said load carrier from thefirst preselected storage area to the second and controlling said drivemeans to accomplish the required direction of movement, said means fordetermining the required direction of movement of said load carrier andfor controlling said drive means including two directiondeterminingswitch means, one for controlling the direction of horizontal trolleyassembly movement and one for controlling the direction of vertical loadcarrier movement, the condition of which switch means is individuallyvaried in response to movement of the transfer unit past the position ofthe second preselected storage area, in a horizontal or verticaldirection, or both, as it travels to the first preselected storage area,and which conditions individually determine whether the horizontal orvertical directions of travel, or both, are reversed to move the loadcarrier to the second storage area and control such reversal.